1. Field of the Invention: The present invention relates, in general, to overhead doors primarily but not limited to use in large installations such as aircraft hangars, warehouses, and the like.
2. Description of the Prior Art: Heretofore, various overhead doors have been developed. Baldwin, U.S. Pat. No. 1,947,691; Premo, U.S. Pat. No. 1,994,785; Mosher, U.S. Pat. No. 2,936,830; Houk, U.S. Pat. No. 3,224,494; Doering, U.S. Pat. No. 4,120,341; DeVore, U.S. Pat. No. 4,177,854; DeVore, U.S. Pat. No. 4,243,091; and Aspenson, U.S. Pat. No. 4,124,055 all disclose overhead doors comprised, in general, of a lower section and an upper section pivotally attached to one another whereby the door can be folded in halves when opened. None of the above patents disclose or suggest the present invention.
A problem prevalent with overhead doors used for large installations such as aircraft hangars, warehouses, and the like is that much power is required to operate door either manually or otherwise. A counter-balanced door eliminates this problem but creates another; i.e., overcoming wind resistance. This invention solves this problem by a unique design that provides very minimum wind resistance in a fully integrated counter-balanced door.